Scrotal testosterone – the next generation

Thisworld-first study demonstrated that the hormone testosterone applied scrotally achieves up to eight times the absorption than when applied to the upper body.

The study, undertaken at the ANZAC Medical Research Institute in Sydney, Australia by Professor David Handelsman, was a single-center, three-phase cross-over pharmacokinetic study of three single doses (12.5mg (0.25mL), 25mg (0.5mL) and 50mg (1mL)) of AndroForte 5 testosterone cream.

The study showed unequivocally that testosterone cream administration to scrotal skin is well tolerated and produces dose-dependent peak serum testosterone concentration at a much lower dose relative to the non-scrotal (upper body) route of application.

The significance of these findings has an important safety and cost impact on patients and their families. In the USA, all FDA approved testosterone gels and solutions are alcohol based and carry a Black Box safety warning about the dangers of passive testosterone transfer to partners and children. Transdermal testosterone products applied to the upper body achieve between 9-14% absorption. This means 86-91% of the testosterone applied to the upper body is residual on the skin surface. Children and female partners can absorb testosterone by making close contact with users which can result in virilizing effects. Transdermal testosterone gels and solutions cannot be applied to the scrotum because the high alcohol content of these products is irritating. The greater capacity of scrotal skin to absorb the alcohol-free testosterone cream, combined with the location of the testes, effectively removes the problems associated with passive transfer.

Plans to underway to conduct an Australia-wide study – the SAFEST study (Scrotal Androgen Efficacy and Safety Trial) – in hypogonadal men commencing in 2018 – with the ultimate aim or US and European regulator approvals.